Lubricants adapt with changing fuels

In April, Castrol launched its refreshed Castrol TLX product range to cater to medium speed four-stroke engines. The reformulated product range will replace Castrol TLX Xtra and TLX Plus fluids and is designed for use with existing fuel types, including residual fuels HSFO, VLSFO, ULSFO, and dual fuel engines operating on residual fuel and gas. It is also suitable for vessels switching fuels and trading in and out of Emissions Control Areas.

“Lubricants are a lever of change as the industry strives to meet multi-tiered and complex regulations, an increased focus on health and safety, mounting demand for reduced downtime and increasing engine performance amid new fuel and engine technology” says Eda Gökay, global marine and energy marketing manager at Castrol.

The new product range has undergone field trials conducted by OEMs and works well even with high-sulphur fuel. low lubricant oil consumption and a small sump size. Castrol says the Castrol TLX range performed in these challenging conditions by removing contamination, oil sludge and water during purification and filtration, helping keep the oil in optimum condition and protecting the engine from corrosion and wear.

Late last year, Chevron Marine Products published a white paper about HDAX 9700, its latest 4-stroke engine oil solution designed for engines that run on liquid and gaseous fuels and require a low sulphated ash lubricant. The oil has secured approval from MAN Energy Solutions for use with its four-stroke engines running on either LNG or distillate fuels with a sulphur content of up to 1,000 parts per million.

The testing with MAN Energy Solution included operation on Jan De Nul Group’s trailing suction hopper dredger and ultra-low emission vessel, Sanderus, which uses low-sulphur diesel fuel. The company required an engine oil with a very low sulphated ash formulation due to the use of a variety of low sulphur fuels (below 0.10% sulphur) with Selective Catalytic Reduction unit and diesel particulate filter. Jan De Nul has subsequently used the lubricant on other vessels.

There are some lubricants which undergo validation testing on engines running on either gas or distillate fuels and are granted limited approval, says Chevron, so the company claims the approval was the first of its kind and offers simplicity for operators switching between the two fuels. They can use just one lubricant, rather than having to change lubricants after a fixed period operating on one fuel or the other. HDAX 9700 has also successfully completed 20,000+ test hours on a Wärtsilä 34 dual-fuel engine.

Lubmarine is pushing ahead with a series of laboratory and at-sea hybrid testing programs to assess formulations that are suitable for engines using NH3 as a fuel, with research being undertaken on a redesigned 1.5 litre passenger car diesel engine. “From an initial perspective, we wanted to show that NH3 can interact with lubricant chemistry, so our challenge is to fully understand its operating behaviours to enable us to adapt lubricant formulations to meet specific needs,” says Dr Olivier Denizart, technical manager at Lubmarine.

To ensure that the engine oil technology allows reliable, clean, and efficient use in NH3-fuelled internal combustion engines, Lubmarine researchers are looking out for challenges such as deposits, wear, corrosion, and oil ageing and are evaluating sensitivity to engine oil composition. “Just a few of the observation and assessment areas when we are running NH3 engine tests include NH3 dilution, nitro-oxidation, corrosion, cylinder wall degreasing, water handling, deposit control and material compatibility,” says Denizart. Lubmarine will start trials on a tug using an NH3-fuelled 4-stroke engine this year.

Lubmarine is also conducting trails with MeOH 2-stroke commercial engines and has analysed the oxidation and other main characteristics of its lubricants where they have been adapted to MeOH-fuelled engines.

Denizart highlights the cyclic nature of development, as from the time the first deliveries of new formulations are made, their performance can be continually monitored in a much wider set of circumstances across a broader set of parameters and operating circumstances. “This data collection not only allows us to monitor the performance, but we also collect the data to support our future R&D work.”

Looking to that future, Denizart says: “The predicted take up of H2 based e-fuels (including e-methanol and e-ammonia) is expected to take place after 2040 and should be significant in some specific applications. It is also anticipated that LNG will remain in the mix but not significantly above the post 2030 volumes. So, we are undoubtedly heading towards a more complex market with multiple fuel solutions making up the landscape.”